Outcast outcast center diff cracking noise in reverse

[Jacobvanemmerik]

Hi everyone,

My name is Jacob, i am 20 years old and live in the Netherlands. I am the proud owner of a arrma outcast since a week, but after 2 runs on 6s the center diff is making a cracking noise, but only in reverse. Pulled it apart and checked it but couldn't find anything, added al little bit of 10k diff oil(thought it was a little low) and put it back together. Next run first 10 min no cracking noise, after that it was there again. repeated the procedure but then before tightening the bolts put a little bit of loctite on it. Than ran it again and the outcast did it again. Is there anyway to fix this? Should i run 4s instead or is that not the problem? love the outcast so far but the sounds creeps me out.... Any help would be very welcome!

 

[chevys10zr2003]

Hi everyone,

My name is Jacob, i am 20 years old and live in the Netherlands. I am the proud owner of a arrma outcast since a week, but after 2 runs on 6s the center diff is making a cracking noise, but only in reverse. Pulled it apart and checked it but couldn't find anything, added al little bit of 10k diff oil(thought it was a little low) and put it back together. Next run first 10 min no cracking noise, after that it was there again. repeated the procedure but then before tightening the bolts put a little bit of loctite on it. Than ran it again and the outcast did it again. Is there anyway to fix this? Should i run 4s instead or is that not the problem? love the outcast so far but the sounds creeps me out.... Any help would be very welcome!

Welcome to the forum Jacob. I'm sorry that you are having issues with your new car. That's never fun. Does it make the noise with the wheels off of the ground, or only when there is a load going through the drive train? Can you take a video of the noise and upload so that we can see exactly the noise that you are talking about?

 

[Jacobvanemmerik]

The noise is only there when the wheels are on the ground. I made a video of it hope it is hearable on the video. Very fast reply by the way! Could find out what video format to use to upload.. So here is a link..

 

[chevys10zr2003]

That actually sounds normal to me. The reason that it is loud is because the entire drive train is metal. Does it sound the same way when you are doing 50% throttle going forward?

 

[Jacobvanemmerik]

That wouldn't explain why I doesn't make the noise after I pull the diff apart and then put it back in... Then after ten minutes it makes that sound again. It also sounds different when I drive forward.

 

[chevys10zr2003]

That wouldn't explain why I doesn't make the noise after I pull the diff apart and then put it back in... Then after ten minutes it makes that sound again. It also sounds different when I drive forward.

Yeah that is weird. I don't know why it goes away and then comes back. Maybe I am also missing something since I am listening to it on my headphones. I know that all three of my Arrmas are loud like that and have been from day one. Hopefully someone else can help out.

 

[Jacobvanemmerik]

That's what I thought... Thanks for the effort anyway!

 

[Jacobvanemmerik]

Welcome to the forum Jacob. I'm sorry that you are having issues with your new car. That's never fun. Does it make the noise with the wheels off of the ground, or only when there is a load going through the drive train? Can you take a video of the noise and upload so that we can see exactly the noise that you are talking about?

I found the problem, the planetary gear that goes to the front tires, skips a few teeth now and then. It also got worse after i ran another pack. Contacting the seller to ask what to do. A gear should not be broken after 3/4 runs right?

 

[chevys10zr2003]

I found the problem, the planetary gear that goes to the front tires, skips a few teeth now and then. It also got worse after i ran another pack. Contacting the seller to ask what to do. A gear should not be broken after 3/4 runs right?

Ideally, no, it should not be broken after 3 to 4 runs, but some people are harder on things than others. Are there teeth broken, or does it just have alignment issues and it just skips them? Was this vehicle new or used when you bought it?

 

[RxMonkey]

Also strongly recommend that you shim the diffs if you haven’t already. There is a guide on the forums on the kraton section. It’s stickied at the top. If you put 10k in the center diff I feel that’s far too thin for the outcast. 100k was way too thin in my opinion. I went to 1 million in my center diff. Especially on 6s the power transfers to the front wheels way too much. That’s likely what abused your front diff.

This is just my opinion but I’d suggest you thicken up the center diff to between 300k-1M. It makes it so the power stays with the back wheels. It’ll wheelie even easier than before but when the front wheels come up they won’t be ballooning. Made a world of difference for me with my outcast.

Not sure what the shipping situation is for you but eBay and Jennysrc are great places to get parts for dirt cheap.

All the best!

 

[Iamtheoutcast]

Welcome to the fourm sorry you have been having issues. I had a similar problem with my outcast. When you open the bulk head is there any indication of metal shavings. I had to take a flashlight to the grease to see tiny shavings. Here it turned out that I had to much play in the 10t which caused it to ride to far forward on the 43t chewing the back of the 10t up. Shimmed everything and replaced 10t solved the issue hope this helps.

 

[Jacobvanemmerik]

Ideally, no, it should not be broken after 3 to 4 runs, but some people are harder on things than others. Are there teeth broken, or does it just have alignment issues and it just skips them? Was this vehicle new or used when you bought it?

New, no teeth broken, just the skipping the teeth.. there were no shims under the planetary gears..

 

[Jacobvanemmerik]

New, no teeth broken, just the skipping the teeth.. there were no shims under the planetary gears..

Seller sent me new gears and shims, will be thickening the diff oils and shimming all Dr diffs, thanks everyone!

 

[joostin420]

@Iamtheoutcast is your truck finished?

 

[Jacobvanemmerik]

Yes it is, put shims in all the diffs. Not having any problems with the gear train. Although my servo just died... Order a 20 kg one as replacement.